{"id":22065,"date":"2020-09-13T05:00:55","date_gmt":"2020-09-13T05:00:55","guid":{"rendered":"https:\/\/www.lifeandnews.com\/articles\/?p=22065"},"modified":"2020-09-17T14:35:22","modified_gmt":"2020-09-17T14:35:22","slug":"what-a-smoky-bar-can-teach-us-about-the-6-foot-rule-during-the-covid-19-pandemic","status":"publish","type":"post","link":"https:\/\/www.lifeandnews.com\/articles\/what-a-smoky-bar-can-teach-us-about-the-6-foot-rule-during-the-covid-19-pandemic\/","title":{"rendered":"What a smoky bar can teach us about the ‘6-foot rule’ during the COVID-19 pandemic"},"content":{"rendered":"

Byron Erath<\/a>, Clarkson University<\/a><\/em>; Andrea Ferro<\/a>, Clarkson University<\/a><\/em>; Goodarz Ahmadi<\/a>, Clarkson University<\/a><\/em>, and Suresh Dhaniyala<\/a>, Clarkson University<\/a><\/em><\/p>\n

When people envision social distancing, they typically think about the \u201c6-foot rule.\u201d<\/p>\n

It\u2019s true that staying 6 feet from other people can reduce the chance of a coronavirus-laden respiratory droplet landing in your eyes, nose or mouth when someone coughs. Most of these droplets are too tiny to see, and people are expelling them into the air all the time \u2013 when they shout, talk or even just breathe.<\/p>\n

But the 6-foot rule doesn\u2019t account for all risks, particularly indoors.<\/p>\n

Think about walking into a room where someone is smoking a cigarette. The closer you are to the cigarette, the stronger the smell \u2013 and the more smoke you\u2019re inhaling. That smoke also lingers in the air. Over time, it won\u2019t matter where you are in the room; the smoke will be everywhere.<\/p>\n

Cigarette smoke comprises particles that are similar in size to the smaller respiratory droplets expelled by humans<\/a> \u2013 the ones that linger in the air the longest<\/a>. While it\u2019s not a perfect analogy, picturing how cigarette smoke moves through different environments, both indoors and outdoors, can help in visualizing how virus-laden droplets circulate in the air.<\/p>\n

As professors<\/a> who study<\/a> fluid dynamics<\/a> and aerosols<\/a>, we have been exploring how COVID-19 circulates and the risks it creates. The 6-foot rule is a good benchmark that\u2019s easy to remember, but it\u2019s important to understand its limitations.<\/p>\n

Aerosols and an 86-year-old rule<\/h2>\n

The 6-foot rule goes back to a paper published in 1934 by William F. Wells<\/a>, who was studying how tuberculosis spreads. Wells estimated that small respiratory droplets evaporate quickly, while large ones rapidly fall to the ground, following a ballistic-like trajectory. He found that the farthest any droplets traveled before either settling or evaporating was about 6 feet.<\/p>\n

While that distance can reduce exposure, it does not provide a complete picture of infection risk from the SARS-CoV-2 virus.<\/p>\n

When people exhale, they expel respiratory droplets with a wide range of sizes. Most are smaller than 10 microns in diameter<\/a>. These can quickly decrease to approximately 40% of their original diameter, or smaller, due to evaporation<\/a>.<\/p>\n

The droplets will not completely evaporate, however. This is because they consist of both water and organic matter, potentially including the SARS-CoV-2 virus. These tiny droplets stay suspended in the air for minutes to hours<\/a>, posing a risk<\/a> to anyone who comes into contact with them. When suspended in the air, these droplets are commonly referred to as aerosols.<\/p>\n